1. Technical Field
The present invention relates to a liquid cartridge that has a circuit board, which has a memory device mounted on a rear surface thereof and is attached to an outer surface of the liquid cartridge in an insertion direction of a resin container main body to be inserted into and mounted on a cartridge mounting portion of a liquid consuming apparatus, and a connection terminal, which is formed on a surface of the circuit board to be contactable with a connector provided in the cartridge mounting portion, thereby allowing the liquid consuming apparatus to read and write information with respect to the memory device.
2. Related Art
A liquid consuming apparatus includes all kinds of apparatuses that consume a liquid supplied from a predetermined portion during the operation. As a representative liquid jetting apparatus, a liquid ejecting apparatus that ejects liquid droplets from an ejecting head is exemplified. Moreover, the liquid ejecting apparatus is not limited to a recording apparatus, such as an ink jet recording apparatus, a copy machine, or a facsimile machine, which ejects ink from a recording head as a liquid ejecting head to a recording material, such as a recording sheet or the like. For example, the liquid consuming apparatus may be an apparatus that ejects a liquid for a specific purpose, instead of ink, from a liquid ejecting head corresponding to the above-described recording head to a material to be ejected corresponding to the recording material, and causes the liquid to be attached to the material to be ejected. In addition, the liquid ejecting head includes, in addition to the above-described recording head, a color material ejecting head that is used to manufacture color filters of a liquid crystal display or the like, an electrode material (conductive paste) ejecting head that is used to form electrodes of an organic electroluminescent (EL) display or a surface emission display (FED), a bioorganic compound ejecting head that is used to manufacture a bio-chip, a sample ejecting head that ejects a sample as a precision pipette, and so on.
The ink jet recording apparatus sends ink, which is stored in an ink cartridge mounted on a cartridge mounting portion in the apparatus to a recording head. The recording head ejects and coats ink droplets to a recording medium, such as a recording sheet or the like, thereby recording images or characters.
In the ink jet recording apparatus, the recording head controls the ejection of the ink droplets using heat or vibration. If idle printing occurs in a state where ink in the ink cartridge is exhausted and ink is not supplied, the recording head may be damaged.
Accordingly, in the ink jet recording apparatus, in order to prevent idle printing of the recording head, it is necessary to monitor the residual quantity of an ink liquid in the ink cartridge.
Further, when the use conditions, for example, full color photograph printing, monochrome text printing, and the like, are different from each other, a difference in color or quantity of an ink liquid to be consumed occurs. Accordingly, in a recent ink jet recording apparatus, some of a plurality of ink cartridges mounted on the apparatus is changed to the ink cartridges according to the use conditions. In such an ink jet recording apparatus, it is necessary to manage the use history regarding whether the ink cartridge mounted on the cartridge mounting portion is a new one or whether a previously used one is remounted.
From such a background, there is suggested an ink cartridge as shown in FIGS. 7 and 8.
An ink cartridge 1 includes a resin container main body 3 that is inserted into and mounted on a cartridge mounting portion 2 of an ink jet recording apparatus, and a circuit board (IC board) 4 that is mounted on an outer surface 3a in an insertion direction of the container main body 3 (an up and down direction in the drawings).
The container main body 3 is an injection-molded product formed of resin. Inside the container main body 3 is formed a liquid storage portion 3b that stores ink to be supplied to the ink jet recording apparatus. A liquid supply port 3c is formed at a lower surface of the container main body 3 so as to supply ink stored in the liquid storage portion 3b to the ink jet recording apparatus.
The circuit board 4 substantially has a rectangular plate shape. As shown in FIG. 9, a memory device (IC chip) 5 is mounted on a rear surface of the circuit board 4. Connection terminals 7 are formed on a front surface of the circuit board 4 so as to serve as input/output terminals with respect to the memory device 5. The connection terminals 7 are pressed into contact with electrical connector terminals 8 provided in the cartridge mounting portion 2 when the ink cartridge 1 is inserted into and mounted on the cartridge mounting portion 2. Accordingly, a control circuit of the recording apparatus connected to the connector terminals 8 can read and write information with respect to the memory device 5.
In such an ink cartridge 1, it is possible to easily manage the ink residual quantity of the recording apparatus by writing information, such as the ink residual quantity or the use history, to the memory device 5.
Until now, the circuit board 4 is attached to the container main body 3 by fitting bosses protruding from the outer surface 3a of the container main body 3 into mounting holes and thermally caulking the front ends of the bosses.
Specifically, the circuit board 4 is provided with an error absorption notched hole 4a and an oval positioning hole 4b as the mounting holes on the outer surface 3a. The error absorption notched hole 4a is provided at the front end side in the insertion direction into the cartridge mounting portion 2 (in FIG. 8, on a lower side) to have an oval shape in the insertion direction. The oval positioning hole 4b is provided at the base end side in the insertion direction. Then, on the outer surface 3a of the container main body 3 are provided an oval boss 9 that substantially has an oval cross-sectional shape corresponding to the error absorption notched hole 4a and a circular boss 10 that substantially has a circular cross-sectional shape corresponding to the positioning hole 4b. 
Here, the bosses 9 and 10 are correspondingly fitted into the mounting holes 4a and 4b of the circuit board 4, and then the front ends of the bosses 9 and 10 protruding from the front ends of the mounting holes 4a and 4b are thermally fastened. Then, the circuit board 4 is fixed to the outer surface 3a of the container main body 3.
As shown in FIGS. 7 and 8, when a lever member 11 is provided on the outer surface 3a, on which the circuit board 4 is provided, so as to anchor the container main body 3 to the cartridge mounting portion 2, the connector terminals 8 are disposed to lean toward the front end side in the insertion direction so as not to interfere with the lever member 11 (see FIG. 9). For this reason, the connection terminals 7 that are provided on the circuit board 4 are also disposed to lean toward the front end side in the insertion direction (that is, on the side of the underlying error absorption notched hole 4a) (for example, see Patent Document 1).
Patent Document 1: JP-A-2004-90624
However, the elution area of the oval boss 9 by thermal caulking is larger than that of the circular boss 10, and as shown in an enlarged view of FIG. 9, a long eluted portion 9a is formed in the insertion direction.
In the known ink cartridge 1 in which the oval boss 9 is located at the front end side in the insertion direction, when the ink cartridge 1 is inserted into and mounted on the cartridge mounting portion 2, the long eluted portion 9a may rub against the connector terminals 8, which causes resin fractions. Then, the resin fractions may be stuck to the connection terminals 7, and thus defective contact may occur between the connector terminals 8 and the connection terminals 7.
In order to prevent the resin fractions, instead of the oval boss 9, a circular boss having a small cross-sectional shape may be provided. In this case, however, the boss may interfere with other parts and be easily damaged at the front end side in the insertion direction into the cartridge mounting portion 2, that is, at the corner of the cartridge main body 3. Accordingly, a boss having an oval shape is formed in order to improve mechanical strength.
The error absorption notched hole 4a, into which the oval boss 9 is fitted, is formed by a two-stage processing shown in FIGS. 10A and 10B. That is, as shown in FIG. 10A, first, a circular hole 12a is formed using a drill or the like. Then, a square hole 12b is punched by a punching die to extend to a lower edge of the board at the width of the circular hole 12a. During punching the square hole 12b, a positional shift Ks or a burr Kb easily occurs.
The error absorption notched hole 4a absorbs a size tolerance of the circuit board 4, and thus its size is set in advance such that the oval boss 9 is loose-fitted thereinto. However, as described above, since the positional shift Ks or the burr Kb occurs, size accuracy is easily deteriorated. Accordingly, as shown in FIG. 4B, when the circuit board 4 is positioned, deflection (positional shift) F1 or F2 occurs with the circular boss 10 as a rotation fulcrum.
As a result, positioning accuracy of the connection terminals 7 disposed on the side of the error absorption notched hole 4a having large deflection F1 or F2 is lowered, and defective contact may occur with respect to the connector terminals 8.